Human colon adenocarcinoma, one of the most common internal solid tumors, has been refractory to therapeutic modalities other than extirpative surgery. Tumor-specific cell membrane antigens will be solubilized from solid tumors and their metastases by noncovalent bond dissociation with sonication and/or 3 M potassium chloride, and purified by chromatographic and preparative polyacrylamide gel electrophoretic techniques, all of which were previously described by the applicant for transplantation antigens, and have been subsequently employed by investigators in cancer research. Fractions demonstrated to be antigenic by elicitation of in vivo cutaneous hypersensitivity reactions in afflicted patients will be further characterized in vitro. Exhaustively washed peripheral lymphocytes of skin test reactive individuals will be confronted with soluble materials to evoke specific immune performances: blastic transformation and release of lymphokines (mitogenic factor, migration inhibition factor, and lymphotoxin). The degree to which the isolated materials possess all of the requisite determinants of tumor immunity will be assessed in blocking experiments by their capacity to bind, block, and/or defuse the immune capacities of isolated host lymphocytes against neoplastic target cells. Cultured colon carcinoma lines have already been initiated and maintained in our laboratory. The tumor specificity of the materials will be insured by precise HL-A tissue typing of patients, by examining immune responses against autochthonous and allogenic fibroblasts, and by investigation of a large number of cultured tumor lines. The project will thus develop specific reagents for colon immunity: soluble surface antigens and cultured tumor target cells.